Method of fabricating light-emitting semiconductor device

Abstract

A light-emitting diode having a silicon substrate on which there are successively formed a buffer layer, a p-type nitride semiconductor layer, an active layer, an n-type nitride semiconductor layer, and a current spreading layer. The current spreading layer is a lamination of a first and a second sublayer arranged alternately a required number of times. Composed of different compound semiconductors, the alternating sublayers of the current spreading layer create heterojunctions for offering the two-dimensional gas effect. The current spreading layer is so low in resistivity in a direction parallel to its major surface from which light is emitted, that the current is favorably spread therein for improved efficiency of light emission. A front electrode in the form of a metal pad is mounted centrally on the major surface of the current spreading layer in ohmic contact therewith.

1 . A method of making a light-emitting semiconductor device of improved efficiency, which comprises: 
 (a) providing a substrate;    (b) successively growing in a gaseous phase a first compound semiconductor layer of a first conductivity type and an active layer and a second compound semiconductor layer of a second conductivity type, in that order, on the substrate;    (c) growing in a gaseous phase a first current spreading sublayer of a first compound semiconductor on the second compound semiconductor layer;    (d) growing in a gaseous phase a second current spreading sublayer of a second compound semiconductor, different from the first compound semiconductor, on the first current spreading sublayer;    (e) repeating steps (c) and (d) a required number of times to provide as many alternations of the first and second current spreading sublayers constituting in combination a current spreading layer;    (f) creating a first electrode electrically coupled to the current spreading layer; and    (g) creating a second electrode electrically coupled to the first com-pound semiconductor layer.    
   
   
       2 . A method of making a light-emitting semiconductor device of improved efficiency, which comprises: 
 (a) providing a growth substrate for growing semiconductors thereon;    (b) growing in a gaseous phase a first current spreading sublayer of a first compound semiconductor on the growth substrate;    (c) growing in a gaseous phase a second current spreading sublayer of a second compound semiconductor, different from the first compound semiconductor, on the first current spreading sublayer;    (d) repeating steps (b) and (c) a required number of times to provide as many alternations of the first and second current spreading sublayers constituting in combination a current spreading layer;    (e) successively growing in a gaseous phase a first compound semiconductor layer of a first conductivity type and an active layer and a second compound semiconductor layer of a second conductivity type, in that order, on the current spreading layer;    (f) creating a bond layer of electrically conducting material on at least either of the second compound semiconductor layer and a support substrate;    (g) joining the support substrate to the second compound semiconductor layer via the bond layer or layers;    (h) removing the growth substrate from the current spreading layer;    (i) creating a first electrode electrically coupled to the current spreading layer; and    (j) crating a second electrode electrically coupled to the second compound semiconductor layer.